package com.hexb.core.utils;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.io.IOException;
import java.security.SecureRandom;

/**
 * @Package : com.hexb.core.utils
 * @Author : hexb
 * @Date : 2018-08-28 16:01
 */
public class DESUtils {


    private final static String DES = "DES";
    private final static String ENCODE = "UTF-8";


    /**
     * Description 根据键值进行加密
     *
     * @param data   待加密数据
     * @param key    密钥
     * @param encode 字符集编码
     * @return
     * @throws Exception
     */
    public static String encrypt(String data, String key, String encode) throws Exception {
        byte[] bt = encrypt(data.getBytes(ENCODE), key.getBytes(encode));
        return new BASE64Encoder().encode(bt);
    }


    /**
     * Description 根据键值进行加密（默认使用utf-8）
     *
     * @param data 待加密数据
     * @param key  密钥
     * @return
     * @throws Exception
     */
    public static String encrypt(String data, String key) throws Exception {
        return encrypt(data, key, ENCODE);
    }


    /**
     * 根据键值进行解密
     *
     * @param data 待解密数据
     * @param key  密钥
     * @return
     * @throws IOException
     * @throws Exception
     */
    public static String decrypt(String data, String key) throws IOException,
            Exception {
        return decrypt(data, key, ENCODE);
    }

    /**
     * 根据键值进行解密
     *
     * @param data 待解密数据
     * @param key  密钥
     * @return
     * @throws IOException
     * @throws Exception
     */
    public static String decrypt(String data, String key, String encode) throws IOException,
            Exception {
        if (data == null)
            return null;
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] buf = decoder.decodeBuffer(data);
        byte[] bt = decrypt(buf, key.getBytes(encode));
        return new String(bt, encode);
    }

    /**
     * Description 根据键值进行加密
     *
     * @param data
     * @param key  加密键byte数组
     * @return
     * @throws Exception
     */
    private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源
        SecureRandom sr = new SecureRandom();

        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);

        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securekey = keyFactory.generateSecret(dks);

        // Cipher对象实际完成加密操作
        Cipher cipher = Cipher.getInstance(DES);

        // 用密钥初始化Cipher对象
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);

        return cipher.doFinal(data);
    }

    /**
     * Description 根据键值进行解密
     *
     * @param data
     * @param key  加密键byte数组
     * @return
     * @throws Exception
     */
    private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
        // 生成一个可信任的随机数源
        SecureRandom sr = new SecureRandom();
        // 从原始密钥数据创建DESKeySpec对象
        DESKeySpec dks = new DESKeySpec(key);
        // 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        SecretKey securetkey = keyFactory.generateSecret(dks);
        // Cipher对象实际完成解密操作
        Cipher cipher = Cipher.getInstance(DES);
        // 用密钥初始化Cipher对象
        cipher.init(Cipher.DECRYPT_MODE, securetkey, sr);
        return cipher.doFinal(data);
    }
}
